Scissors jack



April 19, 1949. w. P. BROWN 2,467,657

SCISSORS JACK Filed May 9, 1946 I 2 Shets-Sheet 1 INVENTOR- W/kw ffimwygar/am YZ@%M April 19, 1949.

w. P. BROWN SCISSORS JACK Filed May 9, 1946 2 Sheets-Sheet 2 I IN VENTOR.

3W WM Patented Apr. 19, 1949 SCISSORS JACK William P. Brown, Detroit,Mich., assignor of forty-nine per cent to Fred Lake, Marion, OhioApplication May 9, 1946, Serial No. 668,430

14 Claims.

This invention relates to jacks for raising and lowering objects, suchas vehicles, and in particular to so-called scissors jacks having togglelinkage mechanisms therein.

One object of this invention is to provide a scissors jack wherein thecrossing links are synchronized and operatively interconnected by crankmechanisms extending from certain of the pivot pins thereof to the crossblocks of the operating screw.

Another object is to provide a scissors jack as set forth in thepreceding object whereby the crank mechanism enables the jack to exert apowerful mechanical advantage which assists in raising and loweringabnormally heavy loads with increased facility, particularly when thejack is in its lowermost position.

Another object is to provide a scissors jack as set forth in thepreceding objects, wherein the operating screw swings during the raisingoperation from an initial position with the end of the screw nearest theoperator tilted downward to a final position with the screw tiltedupward, thereby enabling the operator to insert the operating handle ina very limited space and operate it conveniently during the initialraising action of the jack, when the load is nearest the ground or floorlevel, and the available space is greatly restricted.

Another object is to provide a scissors jack as set forth in thepreceding objects, wherein each crank mechanism consists of a pair ofspaced crank arms fixedly mounted on and secured to the pivot pin, and alink pivotally connecting the end of each crank with one of the crossblocks through which the operating screw shaft passes, thereby providinga powerful yet simple connection therebetween.

Another object is to provide a scissors jack as set forth in the objectimmediately preceding, wherein the crank arms and crank links aredisposed inwardly of the crossing links where they are out of the wayand closely spaced so as to provide a stronger construction.

Other objects and advantages will become apparent during the course ofthe following description of the accompanying drawings, wherein:

Figure 1 is a side elevation of the improved scissors jack of thisinvention, according to a preferred embodiment thereof, showing the jackin its raised position;

Figure 2 is a right-hand elevation of the scissors jack shown in Figure1;

Figure 3 is an approximately horizontal section through the plane of theoperating screw shaft taken along the line 33 in Figure 1; 7

Figure 4 is a horizontal section taken along the line 44 in Figure 1;

Figure 5 is an inclined section through the lower crossing link andcrank mechanism taken along the line 55 in Figure 1;

Figure 6 is a detailed fragmentary vertical section showing one form ofconnection of a crank arm to its pivot pin;

Figure 7 is a perspective view of the connection bushing shown in Figure6; and

Figure 8 is a view similar to Figure 6 but showing a connectionemploying a pivot pin of D- shaped cross-section.

Referring to the drawings in detail, Figure 1 shows a preferredembodiment of the scissors jack of this invention as mounted upon a baseID of plate-like form having upturned ends II to facilitate moving thejack along the ground or floor. Rising from the base H] are spaced pairsof lugs l2 and I3 upon which are pivotally mounted two pairs of lowercrossing links l4 and I5 respectively. The crossing links I5 are mountedupon pivot pins l6 (Figures 1 and 4) of circular cross-section withenlarged outer ends, the pins l6 passing through aligned bores I1 and I8in the crossing links l5 and lugs l3 respectively.

The lower ends of the crossing links M, on the other hand, are providedwith square bores IQ for receiving the opposite ends of a pivot pin 20of square cross-section (Figures 1 and 4), said ends being likewiseenlarged to secure the parts together. The lugs l2 are provided withenlarged circular borers 2i for receiving the peripheries of cylindricalbushings 22 (Figures 6 and 7) which thereby serve as bearing bushings.The bushings 22 have bores 23 of square cross-section corresponding toand receiving the pivot pin 20 of square cross-section.

Likewise mounted on the square-section pivot pin 20 inwardly of the lugsI2 is a pair of crank arms 24 having square bores 25 thereincorresponding to and receiving the square-section pivot pin 20. In thismanner, a rigid and positive mechanical connection is provided betweenthe crank arms 24 and lower crossing links I4. A spacing sleeve 26 ismounted upon the pivot pin 20 (Figures 4 and 5) between the crank arms24 and serves to maintain them securely adjacent the inner surfaces ofthe lugs l2.

The crank arms 24 are relatively short in comparison with the crossinglinks M and at their outer ends (Figure 4) are provided with bores 2!for receiving pivot pins 28 which pass through aligned bores 29 inconnecting links 39 and have their opposite ends enlarged to secure thecrank arms 24 and links 30 together. The upper ends of the connectinglinks 30 (Figures 1 and 3) are bored as at 3| to receive the oppositelyextending projections 32 of the forward cross block 33. The projections32 are in the form of pins integral with the block 93 and also pivotallyreceive the upper ends of the lower crossing links 15 and the lower endsof upper crossing links 34, the links l5 and 34 having bores 35 and 35respectively for this purpose (Figure 3). The outer ends of theprojections 32 are also enlarged to retain the parts in assembly.

The forward cross block 33 is provided with a transverse bore 31 forrotatably receiving the smooth portion 38 of an operating screw shaft39, the latter having a collar 40 and a retaining pin 4| passing througha transverse hole 42 therein. The collar 49 cooperates with anantifriction thrust bearing 43 disposed on the opposite side of thecross block 33 and consisting of a cup-shaped outer race 44 (Figure 1)and an annularly grooved inner race 45 for receiving ball bearings 46.The thrust bearing 43 is held in position against the cross block 33 bya sleeve 4! pinned as at 48 (Figure 1) to the forward end of the screwshaft 39. The latter terminates within the bore 49 of the sleeve 4! toprovide a socket through which a transverse coupling pin 50 extends,passing through holes 5| in the sleeve 41. The coupling pin 50 has itsends projecting transversely from the sleeve 41 and cooperates with theforward end of the bore 49 to receive the end of a conventionaloperating handle (not shown) having means thereon, such as bayonetslots, for releasably engaging the coupling pin 50. Such operat inghandles are well-known and their details form no part of the presentinvention.

The screw shaft 39 is provided with a screwthreaded portion 52 (Figure3) which passes through a correspondingly threaded bore 54 in a rearwardcross block 55. The latter resembles the forward cross block 33 inhaving similar projections 56 extending from the opposite sides thereofand serving as pivot members for pivotally receiving the upper ends ofthe lower crossing links 54, the lower ends of upper crossing links 5'!and the lower ends of upper connecting links 58 similar to the lowerconnecting links 39 and similarly pivoted to the free ends of uppercrank arms 59, likewise similar to the lower crank anms 24. The linksI4, 51 and 58 (Figure 3) are provided with bores 60, GI and 62respectively for this purpose. The projections 56 are also enlarged attheir ends to hold the links [4, 5'! and 58 in assembly.

The pivotal connection between the connecting links 58 and crank arms 59is made by pivot pins 63 identical in construction to the pivot pins 28(Figure 4) and their opposite ends are fixedly secured to asquare-section pivot pin 64 (Figure 1) passing through squared holestherein. The upper ends of the upper crossing shaft 34 are likewiseprovided with squared holes engaging the square-section pivot pin 64which passes through bushings 66 identical with the bushings 22 (Figures6 and '7) and having the same square holes 23 therethrough. The bushings66 are mounted in circular holes 61 passing through spaced lugs 58extending downwardly from and integral with a load rest or saddle 59 ofplatelike form and having upturned ends 10 for preventing the load, suchas a vehicle axle, from accidentally slipping off. The construction ofthe upper pivot pin 64 and its associated parts is identical with thatof the lower pivot pin 20 and its associated parts (Figure 4), hencerequires no duplication of description. The load rest 59 is alsoprovided with forward lugs ll similar to the lugs l3 on the base It] andhaving similar bores 72 (Figure 2) for receiving the pivot pin 13 ofcircular cross-section. The pivot pin 13 passes through bores '14 in theupper ends of the upper crossing links 5'! and the outer ends thereofare enlarged to hold these parts in assembly.

The modification shown in Figure 8 provides a simplified yet positiveconnection between the crank arms 24 and 59 and the crossing links [4and 34 respectively. For this purpose, the pivot in 29 of squarecros:-section is replaced by a pivot pin 15 of D-shaped cross-sectionhaving a fiat portion l6 engaging the corresponding fiat portion 17 of aD-shaped hole 18 in the ends of the crank arms 24 or 59 and the crossinglinks M or 34 to which they are positively connected. The crossing links94 or 34 are provided with similar holes of D-shaped cross-section forreceiving the ends of the pivot pin 35 and the latter passes throughaligned circular bores T9 in the lu s [2 or 63 respectively. Themodification of Figure 8 eliminates the necessity for the bushings 22and 59 (Figures 6 and 7) since the curved portion of the pivot pin 75has a bearing engagement with the bores '19, whereas the flat portions16 and T! provide a positive mechanical engagement which may beadditionally strengthened, if desired, by tack welding thereat.

In this manner, the lower and upper links l4, i5, 34 and 51 provide atoggle linkage primarily actuated by the screw shaft 39 and assisted inits actuation by the crank mechanism including the crank arms 24 and 59and the connecting links or pitmans 30 and 58.

In operation, let it be assumed that the scissors jack is in its raisedposition shown in Figure 1, with a load 8! indicated by the dotted linessupported on the load rest or saddle 59. Such a load, for example, mayconsist of a vehicle with a front axle 8|. To lower the load 8|, theoperator affixes a conventional handle to the sleeve 41 by means of thecoupling pin 50 and rotates the screw shaft 39 in the proper direction.This action causes the cross block 55 to move away from the cross block33, permitting the crossing links l4, I5, 34 and 51 to swing into morenearly horizontal positions. The crank arms 24 and 59, by their positiveconnection with the crossing links l4 and 34 through the connectinglinks 30 and 58, synchronize the motion of these links and prevent theload rest or saddle 69 from moving laterally a sufficient distance tootherwise collapse the jack. The operator continues the turning of thescrew shaft 39 until the load rest 69 approaches the base I 0, itsminimum permissible distance.

To raise the load 8|, the operator reverses the foregoing procedure byrotating the handle and screw shaft 39 in the opposite direction,causing the cross block 55 to be pulled toward the cross block 33, andswinging the links l4, I5, 34 and 5'! into more nearly verticalposition. At the same time, a powerful lifting and synchronizing forceis transmitted through the links 30 and 58, the crank arms 24 and 59 andthe pivot pins 20 and 65 to the respective crossing links [4 and 34 tosynchronize the swinging thereof and provide additional points ofapplication of the lifting force.

While I have shown and described my invention in detail, it is to beunderstood that the same is to be limited only by the appended claims,for many changes may be made without departing from the spirit and scopeof my invention.

What I claim is:

1. A scissors jack comprising a base member, a top member, a togglelinkage interconnecting said members, an operating device operativelyinterconnecting the intermediate portions of said linkage and arrangedto move said portions laterally toward one another whereby to lift saidtop member, and a crank mechanism additionally connecting said operatingdevice with said toggle linkage, said crank mechanism being responsiveto the motion of said operating device to synchronize the upward motionof said top member with the lateral motion of said intermediate linkageportions,

2. A scissors jack comprising a base member, a top member, a togglelinkage interconnecting said members, an operating device operativelyinterconnecting the intermediate portions of said linkage and arrangedto move said portions laterally toward one another whereby to lift saidtop member, and a crank mechanism additionally connecting said operatingdevice with said toggle linkage adjacent one of said members, said crankmechanism being responsive to the motion of said operating device tosynchronize the upward motion of said top member with the lateral motionof said intermediate linkage portions.

3. A scissors jack comprising a base member, a top member, a togglelinkage interconnecting said members, an operating device operativelyinterconnecting the intermediate portions of said linkage and arrangedto move said portions laterally toward one another whereby to lift saidtop member, and a crank mechanism additionally connecting said operatingdevice with said toggle linkage, said crank mechanism comprising a shaftoperatively connected to said linkage adjacent one of said members, acrank arm connected to said shaft, and a pitman connecting said crankarm with said operating device.

4. A scissors jack comprising a base member, a top member, a pair oflaterally spaced across elements disposed between said members, upperand lower pairs of toggle links having their inner ends pivoted to saidcross elements and their outer ends pivoted to said members, anoperating device operatively interconnecting said cross elements andarranged to move said cross elements toward one another, and a crankmechanism additionally connecting one of said cross elements with one ofsaid toggle links remote from said cross elements.

5. A scissors jack comprising a base member, a top member, a pair oflaterally spaced cross elements disposed between said members, upper andlower pairs of toggle links having their inner ends pivoted to saidcross elements and their outer ends pivoted to said members, anoperating device operatively interconnecting said cross elements andarranged to move said cross elements toward one another, and a crankmechanism additionally connecting one of said cross elements with one ofsaid toggle links adjacent one of said members.

6. A scissors jack comprising a base member, a top member, a pair oflaterally spaced cross elements disposed between said members, upper andlower pairs of toggle links having their inner ends pivoted to saidcross elements and their outer ends pivoted to said members, anoperating device operatively interconnecting said cross elements andarranged to move said cross elements toward one another, and a crankmechanism additionally connecting each of said cross elements with oneof said toggle links remote from said cross elements.

7. A scissors jack comprising a base member, a top member, a pair oflaterally spaced cross elements disposed between said members, upper andlower pairs of toggle links having their inner ends pivoted to saidcross elements and their outer ends pivoted to said members, anoperating device operatively interconnecting said cross elements andarranged to move said cross elements toward one another, and a pair ofcrank mechanisms, one crank mechanism connecting one of said crosselements with one of said toggle links adjacent said base member, andthe other crank mechanism connecting the other of said cross elementswith another of said toggle links adjacent said top member.

8. A scissors jack comprising a base member, a top member, a pair oflaterally spaced cross elements disposed between said members, upper andlower pairs of toggle links having their inner ends pivotedto said crosselements and their outer ends pivoted to said members, an operatingdevice operatively interconnecting said cross elements and arranged tomove said cross elements toward one another, and a crank mechanismadditionally connecting one of said cross elements with one of saidtoggle links remote from said cross elements, said crank mechanismcomprising a shaft operatively connected to said linkage adjacent one ofsaid members, a crank arm connected to said shaft, and a pitmanconnecting said crank arm with said operating device.

9. A scissors jack comprising a base member, a top member, a pair oflaterally spaced cross elements disposed between said members, upper andlower pairs of toggle links having their inner ends pivoted to saidcross elements and their outer ends pivoted to said members, anoperating device operatively interconnecting said cross elements andarranged to move said cross elements toward one another, and a pair ofcrank mechanisms, one crank mechanism connecting one of said crosselements with one of said toggle links adjacent said base member, andthe other crank mechanism connecting the other of said cross elementswith another of said toggle links adjacent said top member, each crankmechanism comprising a shaft operatively connected to said linkageadjacent one of said members, a crank arm connected to said shaft, and apitman connecting said crank arm with said operating device.

10. A scissors jack comprising a base member, and a top member eachcarrying two pairs of spaced pivots thereon, forward and rearwardlaterally spaced cross elements disposed between said members and havingspaced pivots thereon, forward and rearward pairs of lower linksinterconnecting said base member pivots and said forward and rearwardcross element pivots respectively, forward and rearward pairs of upperlinks interconnecting said top member pivots and said forward andrearward cross element pivots respectively, an operating device,operatively interconnecting said cross elements and arranged to movesaid cross elements toward one another, and a crank mechanismadditionally and operatively connecting one of said cross elements withone of said links through one of said pivots.

11. A scissors jack comprising a base member, and a top member eachcarrying two pairs of spaced pivots thereon, forward and rearwardlaterally spaced cross elements disposed between said members and havingspaced pivots thereon, forward and rearward pairs of lower linksinterconnecting said base member pivots and said forward and rearwardcross element pivots respectively, forward and rearward pairs of upperlinks interconnecting said top member pivots and said forward andrearward cross element pivots respectively, an operating deviceoperatively interconnecting said cross elements and arranged to movesaid cross elements toward one another, and

a. crank mechanism additionally and operatively connecting one of saidcross elements with one of said links through one of said pivots, saidcrank mechanism comprising a crank arm rigidly connected to one of saidmember pivots, said last-mentioned pivot being rigidly connected to saidlast-mentioned link, and a pitman connecting said crank arm with one ofsaid cross element pivots.

12. A scissors jack comprising a base member and a top member eachcarrying two pairs of spaced pivots thereon, forward and rearwardlaterally spaced cross elements disposed between said members and havingspaced pivots thereon, forward and rearward pairs of lower linksinterconnecting said base member pivots and said forward and rearwardcross element pivots respectively, forward and rearward pairs of upperlinks interconnecting said top member pivots and said forward andrearward cross element pivots respectively, an operating deviceoperatively interconnecting said cross elements and arranged to movesaid cross elements toward one another, and a pair of crank mechanisms,one crank mechanism connecting one of said cross elements with one ofsaid lower links through one of said base member pivots, and the othercrank mechanism connecting the other of said cross elements with one ofsaid upper links through one of said top member pivots.

13. A scissors jack comprising a base member and a top member eachcarrying two pairs of spaced pivots thereon, forward and rearwardlaterally spaced cross elements disposed between said members and havingspaced pivots thereon, forward and rearward pairs of lower linksinterconnecting said base member pivots and said forward and rearwardcross element pivots respectively, forward and rearward pairs of upperlinks interconnecting said top member pivots and said forward andrearward cross element pivots respectively, an operating deviceoperatively interconnecting said cross elements and arranged to movesaid cross elements toward one another, and a pair of crank mechanisms,one crank mechanism connecting one of said cross elements with one ofsaid lower links through one of said base member pivots, and the othercrank mechanism connecting the other of said cross elements with one ofsaid upper links through one of said top member pivots, saidlast-mentioned base member pivot and top member pivot being rigidlyconnected to their respective lower and upper links.

14. A scissors jack comprising a base member and a top member eachcarrying two pairs of spaced pivots thereon, forward and rearwardlaterally spaced cross elements disposed between said members and havingspaced pivots thereon, forward and rearward pairs of lower linksinterconnecting said base member pivots and said forward and rearwardcross element pivots respectively, forward and rearward pairs of upperlinks interconnecting said top member pivots and said forward andrearward cross element pivots respectively, an operating deviceoperatively interconnecting said cross elements and arranged to movesaid cross elements toward one another, and a pair of crank mechanisms,one crank mechanism connecting one of said cross elements with one ofsaid lower links through one of said base member pivots, and the othercrank mechanism connecting the other of said cross elements with one ofsaid upper links through one of said top member pivots, each crankmechanism comprising a crank arm rigidly connected to one of said memberpivots, said last-mentioned member pivots being rigidly connected to itsrespective link, and a pitman connecting said crank arm with one of saidcross element pivots.

WM. P. BROWN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 4,399,736 Benjamins Dec. 3, 1921=.1,526,767 Benjamins Feb. 1'7, 1925 i-1,954,558 Conrad Apr. 10, 1934

